Sealing means for rotary mechanisms



June 20, 1967 KELL 3,325,455

SEALING MEANS FOR ROTARY MECHANISMS Filed May 14, 1965 IN VENTOR.

BY Wai/uwg'e/ 6? /f// ATTORNEY United States Patent 3,326,455 SEALING MEANS FOR ROTARY MECHANISMS Nathaniel B. Kell, Indianapolis, Ind., assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed May 14, 1965, Ser. No. 455,747 4 Claims. (Cl. 230145) ABSTRACT OF THE DISCLOSURE A sealing assembly for a rotary engine having a multilobed epitrochoidally-shaped cavity wherein sealing strips, pivotally supported by the rotor, are continuously located at a predetermined angle with respect to the cavity wall by a rotor-housed gear and eccentric arrangement connected to the engine crankshaft.

The conventional rotary engine includes an outer body I or stator having a multi-lobed epitrochoidally-shaped cavity therein. An inner body or rotor is rotatable within the cavity and includes a plurality of circumferentially spaced apex portions having sealing means engageable with the cavity wall to provide a plurality of scaled working chambers between the rotor and the outer body which vary in volume upon relative rotation of the two bodies.

The conventional sealing means includes seal strips fitting into slots in the apex portions and extending the axial length of the rotor. The seal strips are fixedly located in planes passing generally through the rotor apex and the rotor center, and therefore become inclined at continuously variable acute angles with respect to a plane moving normal to the epitrochoidal surface of the cavity wall during rotation of the rotor relative to the outer body. This inclination causes irregular wear patterns on both the seal strips and the cavity wall and also chattering and wedging of the seal strips.

This invention overcomes these undesirable features by providing means to maintain the sealing means in a predetermined angular position with respect to the cavity wall as the rotor rotates to prevent irregular Wear patterns and to eliminate chattering and wedging of the seal strips.

Accordingly, an object of the invention is to provide improved means for sealing the working chambers of rotary mechanisms.

Another object of the invention is to provide sealing means for rotary mechanisms which are angularly movable relative to the rotor and are always properly orientated with respect to the cavity wall of the mechanism.

A further object of the invention is to provide sealing means for the working chambers of a rotary mechanism which will be free of chattering or wedging against the cavity wall during operation of the mechanism.

These and other objects of the invention will become apparent upon a reading of the following detailed description of a preferred embodiment of the invention taken in connection with the accompanying drawings in which:

FIGURE 1 is a partially broken away view of a rotary mechanism embodying sealing means according to the invention;

FIGURE 2 is an enlarged sectional view taken generally along the plane indicated by line 2-2 of FIGURE 1; and

FIGURE 3 is an enlarged sectional view taken generally along the plane indicated by line 33 of FIG- URE 1.

Referring to FIGURE 1, a conventional rotary engine includes an outer body 12 having a cavity 14. When viewed in a plane transverse to the axis 16 of the outer body, the cavity wall 18 has the general shape of a two- 3,326,455 Patented June 20, 1967 lobed epitrochoid. The engine, of course, may have a variable number of lobes.

An inner body or rotor 20 is disposed within the outer body 12 for relative rotation thereto and includes a body 22 and axially spaced covers 24 attached to each side of body 22 by suitable fasteners 26. The rotor is generally triangular in shape with arcuate sides and has three circumferentially spaced apex portions 28. The number of these apex portions may vary and is preferably one more in number than the number of lobes of the epitrochoidal shape of the cavity 14. These apex portions 28 mount sealing means 29 according to this invention which cooperate With the cavity wall 18 to provide a plurality of working chambers 30 between the rotor 20 and the outer body 12 which vary in volume upon relative rotation of the two bodies.

A crankshaft 32 is coaxial with the outer body 12 and rotates within the cavity 14. The crankshaft 32 has an eccentric portion 34 upon which the rotor 20 is mounted by bearings 36 and 38 for rotation about an axis 40 parallel to the axis 16 of outer body 12. Crankshaft 32 and rotor 20 rotate in the same direction, but at different speeds. In this embodiment, the rotor 26 rotates at onethird the speed of the crankshaft 32. This speed ratio is enforced by conventional gearing not shown in the drawing.

Each sealing means 29 includes a seal strip 42 in substantially continuous sealing engagement with the cavity wall 18. While the seal strips 42 are shown in FIGURE 1 as including three independent blades they may include any number of blades. Each of the sealing means 29 is identical and therefore only one is described herein. The seal strip 42 extends outwardly through a slot 44 in the apex portion 28. The slot 44 and the seal strip 42 extend across the full axial width of the rotor 20. The beveled outer edges of the slot 44 provide clearance for angular movement of the seal strip 42 within the slot. The inner end portion of the seal strip 42 is received within a slot 46 of a rocker arm 48. The rocker arm includes a cylindrically shaped head 50 seated within complementary shaped grooves 52 of rotor 20 to swingably mount the rocker arm thereon. Heat resistant packing strips 56 prevent both loss of lubricant from the interior of rotor 20 and the passage of combustion gases from the cavity 14 into the rotor 20.

The inner end of the rocker arm 48 includes a forked portion 58 which receives a pin 60 eccentrically mounted on a rotatable sleeve 62 and driven by the crankshaft 32 through a gear arrangement 64. The gear arrangement 64 includes a helical drive gear 66 on the eccentric portion 34 of the crankshaft 32 which meshes with a gear 68 mounted on the shaft 70. A worm gear 72 on shaft meshes with gear 74 on sleeve 62 to rotate the sleeve upon rotation of the crankshaft 32. The rotatable sleeve 62 rotates on stationary pin 76. Shaft 70 is supported in bearings 78 and 80 and is retained within the rotor 20 by the retainer 82.

As the crankshaft 32 rotates clockwise, as viewed in FIGURE 1, the rotor 20 rotates clockwise at one-third the speed of the crankshaft. Thus, the crankshaft will complete three revolutions in the time that it takes the rotor to complete one. This rotation of the crankshaft ahead of the rotor is used to drive the seal strip actuating mechanism.

The gears 66, 68, 72 and 74 are conventionally arranged to rotate sleeve 62 and pin 60 in the same direction and at the same rotational speed as the crankshaft 32 and in turn to oscillate the seal strip 42 within slot 44 as the seal strip moves with rotor 20. Oscillation of the seal strip in this manner maintains it in a position which is at all times generally perpendicular to the cavity wall.

The invention thus provides an improved means for sealing the working chambers of a rotary engine in which the sealing means are angularly movable with respect to the rotor so as to be always properly oriented with respect to the cavity wall, thereby preventing irregular Wear of the seal strips and the cavity Wall and eliminating chattering or wedging of the seal strips.

What is claimed is:

1. A rotary mechanism comprising an outer body having a Wall forming a cavity therein, an inner body disposed within said outer body for rotation relative thereto, said inner body having a plurality of portions cooperable with the cavity wall to form a plurality of working chambers between said bodies that vary in volume upon relative rotation of said bodies, sealing means pivotally associated with said portions and engaging said cavity wall, and means operatively associated with said inner body for selectively rotating said sealing means to continuously locate said sealing means at a substantially predetermined position with respect to said cavity wall as said inner body rotates relative to said outer body.

2. A rotary mechanism comprising an outer body having a Wall forming a cavity therein, an inner body disposed within said outer body for rotation relative thereto, said inner body having a plurality of portions thereof cooperable with the cavity wall to form a plurality of working chambers between said bodies that vary in volume upon relative rotation of said bodies, a movable member pivotally mounted within each of said portions, sealing means received within each of said movable members and extending outwardly therefrom into engagement with said cavity wall, and means operatively associated with said inner body for selectively rotating said sealing means to continuously locate said sealing means at a substantially predetermined position with respect to said cavity wall as said inner body rotates relative to said outer body.

3. A rotary mechanism comprising an outer body having a wall forming a cavity therein, an inner body disposed within said outer body for relative rotation thereto, said inner body having a plurality of portions thereof cooperable with the cavity wall to form a plurality of working chambers between said bodies which vary in volume upon relative rotation of said bodies, a rocker arm pivotally mounted at each of said portions and having a slot at one end and a forked portion at the opposite end, sealing means received within said slots and extending outwardly therefrom into engagement with said cavity wall, eccentrically driven pins drivingly engaging said forked portions, and means driving said pins to continuously locate said sealing means at a substantially predetermined angle with respect to said cavity wall as said inner body rotates relative to said outer body.

4. A rotary mechanism comprising an outer body having a Wall forming a cavity therein, a crankshaft rotating Within said cavity, a rotor journalled on an eccentric portion of said crankshaft, said rotor being disposed within said outer body for rotation relative thereto and having a number of circumferentially spaced apex portions cooperating with the cavity wall to form a plurality of working chambers that vary in volume upon relative rotation of said rotor and said outer body, a rocker arm at each apex portion pivotally attached to the rotor so that it may be made to oscillate and having a slot at one end and a forked portion at the other end, sealing means at each end of said apex portions received Within said slots and said rocker arms so as to be movable therewith and extending outwardly therefrom into engagement with said cavity wall, eccentrically driven pins drivingly engaging said forked portions, and a gear arrangement transmitting driving power from said crankshaft to said pins, said gear arrangement adapted to continuously locate said sealing means at a substantially predetermined angle with respect to said cavity wall as said inner body rotates relative to said outer body.

References Cited UNITED STATES PATENTS 1,818,430 8/1931 Ricardo 103--140 1,952,142 3/1934 Peterson 230154 2,555,678 6/1951 Cornwell 103-136 3,159,336 12/1964 Paschke 230 3,169,695 2/1965 Wankel 230--154 3,189,263 6/1965 Ansorg 230145 3,205,872 9/1965 Pomasanow 1238 FOREIGN PATENTS 1,347,541 11/1963 France.

126,924 1/1902 Germany.

217,479 1/1910 Germany.

DONLEY J. STOCKING, Primary Examiner.

WILBUR J. GOODLIN, Assistant Examiner. 

1. A ROTARY MECHANISM COMPRISING AN OUTER BODY HAVING A WALL FORMING A CAVITY THEREIN, AN INNER BODY DISPOSED WITHIN SAID OUTER BODY FOR ROTATION RELATIVE THERETO, SAID INNER BODY HAVING A PLURALITY OF PORTIONS COOPERABLE WITH THE CAVITY WALL TO FORM A PLURALITY OF WORKING CHAMBERS BETWEEN SAID BODIES THAT VARY IN VOLUME UPON RELATIVE ROTATION OF SAID BODIES, SEALING MEANS PIVOTALLY ASSOCIATED WITH SAID PORTIONS AND ENGAGING SAID CAVITY WALL, AND MEANS OPERATIVELY ASSOCIATED WITH SAID INNER BODY FOR SELECTIVELY ROTATING SAID SEALING MEANS TO CONTINUOUSLY LOCATE SAID SEALING MEANS AT A SUBSTANTIALLY PREDETERMINED POSITION WITH RESPECT TO SAID CAVITY WALL AS SAID INNER BODY ROTATES RELATIVE TO SAID OUTER BODY. 